Jaw roll joint

ABSTRACT

A surgical instrument includes a handle, and an elongated shaft extending from the handle. An end effector extending from the elongated shaft is in communication with a source of electrosurgical energy and defines an end effector axis. A roll joint couples the end effector to the elongated shaft and includes a first tubular structure extending distally from the elongated shaft and a second tubular structure rotatably coupled to the first tubular structure. The second tubular structure supports the end effector such that the end effector is rotatable about the end effector axis.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit as a continuation application ofU.S. patent application Ser. No. 13/847,350, filed Mar. 19, 2013, whichis a continuation of U.S. patent application Ser. No. 12/609,284, filedOct. 30, 2009, now U.S. Pat. No. 8,398,633. The entire contents of eachof the above applications is hereby incorporated by reference.

BACKGROUND 1. Technical Field

The present disclosure relates to a surgical apparatus having anelongated shaft for laparoscopic and endoscopic procedures. Inparticular, the disclosure relates to a surgical apparatus having a rolljoint permitting an end effector to rotate relative to a distal portionof the elongated shaft.

2. Background of Related Art

Typically in a laparoscopic, an endoscopic, or other minimally invasivesurgical procedure, a small incision or puncture is made in a patient'sbody. A cannula is then inserted into a body cavity through theincision, which provides a passageway for inserting various surgicaldevices such as scissors, dissectors, retractors, or similarinstruments. To facilitate operability through the cannula, instrumentsadapted for laparoscopic surgery typically include a relatively narrowshaft supporting an end effector at its distal end and a handle at itsproximal end. Arranging the shaft of such an instrument through thecannula allows a surgeon to manipulate the handle from outside the bodyto cause the end effector to carry out a surgical procedure at a remoteinternal surgical site. This type of laparoscopic procedure has provenbeneficial over traditional open surgery due to reduced trauma, improvedhealing and other attendant advantages.

A steerable laparoscopic or endoscopic instrument may provide a surgeonwith a range of operability suitable for a particular surgicalprocedure. For example, the instrument may be configured such that theend effector may be aligned with a longitudinal axis of the instrumentto facilitate insertion through a cannula, and thereafter, the endeffector may be caused to articulate or move off-axis as necessary toappropriately position the end effector to engage tissue. When the endeffector of a steerable, articulating instrument comprises a pair of jawmembers for grasping tissue, the jaw members may need to be orientedrelative to the tissue once properly positioned. Orienting the jaws mayinvolve rotating the jaws about the longitudinal axis. However, thistype of rotation may frustrate the positioning of the end effector. Aroll joint disposed at a distal end of the elongated shaft may alleviatesome of the difficulties and facilitate adjustments to either theposition or the orientation of the jaws as the end effector approachesthe targeted tissue.

One type of laparoscopic instrument is intended to generate asignificant closure force between jaw members to seal small diameterblood vessels, vascular bundles or any two layers of tissue with theapplication electrosurgical or RF energy. The two layers may be graspedand clamped together by the jaws, and an appropriate amount ofelectrosurgical energy may be applied through the jaws. In this way, thetwo layers of tissue may be fused together. Many electrosurgical forcepsinclude a conductor extending through the elongated to provide the endeffector with an electrosurgical current. In some instances, theconductor may become entangled or may limit the range of motionachievable by the end effector. To offer a surgeon control of such aninstrument a roll joint may be provided to facilitate passage of theelectrosurgical current therethrough.

SUMMARY

The present disclosure describes a surgical instrument including ahandle having an elongated shaft extending distally therefrom. Theelongated shaft defines a longitudinal axis. An end effector extendsdistally from the elongated shaft and defines an end effector axis. Theend effector is in communication with a source of electrosurgicalenergy. A roll joint couples the end effector to the elongated shaft andincludes a first tubular structure extending distally from the elongatedshaft, and a second tubular structure rotatably coupled to the firsttubular structure about the end effector axis. The second tubular membersupports the end effector such that the end effector is rotatable withrespect to the first tubular structure about the end effector axis. Acable wrap volume is disposed within at least one of the first andsecond tubular structures, and a conductor for coupling the end effectorwith the source of electrosurgical energy is coiled about the endeffector axis within the cable wrap volume. Rotation of the end effectorabout the end effector axis in a first direction unwinds the conductor.

The roll joint further may include a structural stop protruding from oneor both of the first and second tubular structures to engage the othertubular structure to limit rotation of the end effector. The first andsecond tubular structures may be coupled to one another by a bearingset.

The elongated shaft may include an articulating portion disposedproximally of the roll joint wherein the articulating portion isflexible to permit pivotal motion of the end effector with respect tothe longitudinal axis. The second tubular structure may be coupled to adrive member that extends through the articulating portion of theelongated shaft and is configured to transmit torque to the secondtubular structure.

The end effector may include a pair of opposable jaw members movablebetween an open configuration for receiving tissue and a closedconfiguration for maintaining a closure pressure on the tissue. The endeffector may be coupled to a reciprocating member that is longitudinallymovable to induce movement of the jaw members between the open andclosed configurations. The reciprocating member may extend through alongitudinal bore through the roll joint.

According to another aspect of the disclosure a surgical instrumentincludes a handle having an elongated shaft extending distally from thehandle. The elongated shaft includes a proximal portion coupled to thehandle and a distal portion pivotally coupled to the proximal portion.The proximal portion defines a longitudinal axis. An end effectordefines an end effector axis and is in communication with a source ofelectrosurgical energy by an electrosurgical conductor extending throughthe elongated shaft. A roll joint is disposed between the distal portionof the elongated shaft and the end effector. The roll joint includes afirst tubular structure coupled to the distal portion of the elongatedshaft and a second tubular structure coupled to the end effector. Thesecond tubular structure is rotatably coupled to the first tubularstructure such that the end effector is rotatable about the end effectoraxis.

The electrosurgical conductor may be coiled about the end effector axiswithin the first tubular structure such that rotation of the endeffector about the end effector axis unwinds the electrosurgicalconductor. Alternatively, the electrosurgical conductor may be coupledto a conductive slip ring disposed within the first tubular structure,and an electrically conductive receptor may be coupled to the secondtubular structure such that the receptor maintains electrical contactwith the slip ring regardless of the rotational position of the secondtubular structure with respect to the first tubular structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the presentdisclosure and, together with the detailed description of theembodiments given below, serve to explain the principles of thedisclosure.

FIG. 1 is a perspective view of a surgical instrument in accordance withthe present disclosure including an end effector aligned with alongitudinal axis;

FIG. 2A is a partial, perspective view of a distal end of the instrumentof FIG. 1 depicting the end effector in an articulated position withrespect to the longitudinal axis;

FIG. 2B is a partial, perspective view of the distal end of theinstrument of FIG. 2A depicting the end effector in a rotated positionwith respect to a shoulder axis;

FIG. 2C is a partial, perspective view of the distal end of theinstrument of FIG. 2B depicting the end effector in a rotated positionwith respect to a wrist axis;

FIG. 2D is a partial perspective view of the distal end of theinstrument of FIG. 2C depicting the end effector in a closedconfiguration;

FIG. 3 is a partial side view of the instrument of FIG. 1 having ahousing component removed and depicting a coaxial drive mechanism;

FIG. 4 is a cross-sectional perspective view of the drive mechanism ofFIG. 3 in a first or “home” configuration for maintaining the endeffector in alignment with the longitudinal axis;

FIG. 5 is an enlarged, cross-sectional, partial perspective view of thedrive mechanism in a second configuration for articulating the endeffector with respect to the longitudinal axis;

FIG. 6A is a schematic view of a tendon preload and locking device;

FIG. 6B is a schematic view of an alternate embodiment of a tendonpreload and locking device depicting a movable guide having a camsurface;

FIG. 6C is a schematic view of an alternate embodiment of a tendonpreload and locking device depicting a movable guide for exerting anoutwardly directed force on a tendon;

FIG. 7 is an enlarged, cross-sectional, partial perspective view of thedrive mechanism in a third configuration for effecting a shoulder rollof the distal end of the instrument;

FIG. 8 is an enlarged, cross-sectional, partial perspective view of thedrive mechanism in a fourth configuration for locking the distal end ofthe instrument in the shoulder roll configuration;

FIG. 9 is an enlarged, cross-sectional, partial perspective view of thedrive mechanism in a fifth configuration for effecting a wrist roll ofend effector;

FIG. 10A is schematic view of a wrist roll joint at the distal end ofthe instrument;

FIG. 10B is a schematic view of an alternate embodiment of a roll joint;

FIG. 11 is an enlarged, cross-sectional, partial perspective view of thedrive mechanism in a sixth configuration for closing a pair of jawmembers at the end effector;

FIG. 12 is an enlarged, cross-sectional, partial perspective view of thedrive mechanism in a seventh configuration for advancing a knife throughthe pair of jaw members;

FIG. 13 is a partial side view of the instrument depicting a knife lockmechanism to permit advancement of the knife only after the pair of jawmembers has been closed; and

FIGS. 14A through 14D are perspective views depicting various individualcomponents of the drive mechanism including an articulation sphere(14A), an articulation spool (14B), a shoulder roll knob (14C), and alocking collar (14D).

DETAILED DESCRIPTION

Referring initially to FIG. 1, a steerable endoscopic instrument isdepicted generally as instrument 10. Instrument 10 includes a handle 12near a proximal end, an end effector 16 near a distal end and anelongated shaft 18 therebetween. Elongated shaft 18 includes a proximalportion 20 extending from the handle 12 and an articulating distalportion 22 supporting the end effector 16. The proximal portion 20defines a longitudinal axis A-A, and is sufficiently long to positionthe end effector 16 through a cannula (not shown). At least one joint 28is established between the proximal and distal portions 20, 22 of theelongated shaft 18 permitting the distal portion 22 and the end effector16 to articulate or pivot relative to the longitudinal axis A-A asdescribed in greater detail below (see FIG. 2A). The end effector 16defines an end effector axis B-B, which is aligned with the longitudinalaxis A-A when the articulating distal portion 22 of the elongated shaft18 is in a “home” configuration.

The end effector 16 includes a pair of opposing jaw members 30 and 32.The jaw members 30, 32 are operable from the handle portion 12 to movebetween an open configuration to receive tissue, and a closedconfiguration (see FIG. 2D) to clamp the tissue and impart anappropriate clamping force thereto. When the end effector 16 is in theopen configuration, a distal portion of each of the jaw members 30, 32is spaced from the distal portion of the other of the jaw members 30,32. When the end effector 16 is in the closed configuration, the distalportions of the jaw members 30, 32 are closer together. The end effector16 is configured for bilateral movement wherein both jaw members 30 and32 move relative to the end effector axis B-B as the end effector 16 ismoved between the open and closed configurations. However, unilateralmotion is also contemplated wherein one of the jaw members, e.g., 32remains stationary relative to the end effector axis B-B and the otherof the jaw members, e.g., 30 is moveable relative to the axis B-B.

Handle 12 is manipulatable by the surgeon from outside a body cavity tocontrol the positioning, orientation and operation of the end effector16 when the end effector 16 is positioned inside the body at a tissuesite. To provide this operability, the handle 12 supports variousactuators that are operable to induce movement in the end effector 16through various modes. These actuators include an articulation trigger40, which is operable to articulate the distal portion 22 of theelongated shaft 18 with respect to the longitudinal axis A-A (see FIG.2A), a shoulder roll knob 42, which is operable to rotate thearticulating distal portion 22 about the longitudinal axis A-A (see FIG.2B), and a wrist roll knob 44, which is operable to rotate the endeffector 16 about the end effector axis B-B (see FIG. 2C). Thearticulation trigger 40, wrist roll knob 44 and shoulder roll knob 42cooperate to permit the end effector 16 to be appropriately positionedand oriented in a three dimensional environment to effectively engagetissue. Once the end effector 16 is positioned and oriented, the surgeonmay approximate a pivoting handle 46 relative to a stationary handle 48to move the jaw members 30, 32 to the closed position (see FIG. 2D).

The surgeon may also manipulate a finger trigger 50 to lock the pivotinghandle 46 in an approximated position with respect to the stationaryhandle 48, and thus maintain the jaw members 30, 32 in the closedconfiguration. When the jaw members 30, 32 are in the closedconfiguration, the surgeon may initiate the delivery of electrosurgicalenergy to the jaw members 30, 32 by manipulating a push button 50 aprovided on the handle 12. In alternate embodiments, the delivery ofelectrosurgical energy may be initiated with the finger trigger 50.

Additionally, handle 12 supports a locking lever 52 that is operable toprevent unintended actuation of the articulation trigger 40 and shoulderroll knob 42. Thus, the end effector 16 may be maintained in a stableposition. Also, a knife spool 54 is supported at a proximal end of thehandle 12. The knife spool 54 is operable to advance a knife blade 54 a(see FIG. 2B) through the jaw members 30, 32. With the exception of thefinger trigger 50 and the push button 50 a, each of the actuatorsdescribed above transmits mechanical motion to the end effector 16through a drive assembly 100 (see FIG. 3). The operation of the driveassembly 100 is discussed in greater detail below.

Push button 50 a is in electrical communication with a source ofelectrosurgical energy such as electrosurgical generator 50 b. Theelectrosurgical generator 50 b serves to produce electrosurgical energyand also to control and monitor the delivery of the electrosurgicalenergy. Various types of electrosurgical generators 50 b, such as thosegenerators provided by Covidien—Energy-based Devices, of Boulder, Colo.,may be suitable for this purpose. Electrosurgical generator 50 b may behoused within the stationary handle 48 as depicted schematically in FIG.1, or may alternatively be electrically and mechanically coupled to theinstrument 10 by a cable (not shown). The electrosurgical generator 50 bis in electrical communication with at least one of the jaw members 30,32.

Referring now to FIG. 2A, the end effector 16 is moved in anarticulation mode in the direction of arrow “A0,” or generally to theright from a perspective of a user. In this articulated position, theend effector axis B-B is oriented at an articulation angle “α” withrespect to the longitudinal axis A-A. Any angle “α” may be achieved bybending distal portion 22 of the elongated shaft 18 to an appropriatedegree. The distal portion 22 includes a plurality of segments 56 thatare nested with one another such that each segment 56 is pivotallyarranged with respect to a neighboring segment 56. Each segment 56 isconstructed in a similar manner and includes a pair of steering bores 58extending therethrough. The steering bores 58 are laterally arrangednear an outer circumference of the link 56 and have a radial spacing ofabout 180 degrees. Thus, the steering bores 58 define a plane ofarticulation in which the distal 22 may bend. Although the distalportion 22 of the elongated shaft 18 may articulate in a single plane ofarticulation, other embodiments are also envisioned in which additionalsteering bores (not shown) permit articulation in multiple planes ofarticulation.

The steering bores 58 permit passage of a pair of steering tendons 110(see also FIG. 4). The steering tendons 110 are coupled to a leadingsegment 56 a such that a tension imparted to one of the steering tendons110 is transferred to the leading segment 56 a. Thus, the distal portion22 of the elongated shaft 18 may be articulated. For example, a tendon110 disposed through the bores 58 on the right side of the distalportion 22 may be pulled proximally in the direction of arrow “A4” todraw the right side of the leading segment 56 a proximally, and to curvethe distal portion 22 to the right. Similarly, the distal portion 22 maybe curved to the left by drawing the opposite tendon 110 proximally.

Each of the segments 56 includes a central bore (not shown) extendingtherethrough. The central bore permits passage of various componentsthrough the distal portion 22 to the end effector 16. For example, anelectrosurgical conductor 178 (FIG. 10A) may pass through the distalportion 22 to provide electrosurgical energy to the end effector 16.Control cables, flexible rods, and torsion members may also be passedthrough the central bores to transfer mechanical motion to the endeffector 16 as discussed in greater detail below. Although the distalportion 22 of the elongated shaft 18 has been described as including aplurality of pivoting segments 56, other embodiments are contemplated inwhich a single pivot joint is provided to orient the end effector axisB-B at angle “α” with respect to the longitudinal axis A-A.

Referring now to FIG. 2B, the end effector 16 is moved through a secondmode of motion herein referred to as a “shoulder roll.” In the shoulderroll mode, the end effector 16, the distal portion 22 of the elongatedshaft 18 and an outer tubular member 60 of the elongated shaft are allconcurrently rotated about the longitudinal axis A-A as indicated byarrows “S0.” The end effector 16 is maintained at the angle “α,” and isswept through a three dimensional arc “β” such that the position of theend effector 16 is moved from the right generally to the left from theperspective of a user. The shoulder roll may be continued until anydesired angle “β” is achieved. Since any angle “α” and any angle “β” isachievable, the end effector 16 may be positioned at any appropriateposition in a three dimensional environment.

A knife blade 54 a (depicted in phantom) is advanceable through the jawmembers 30, 32 in the direction of arrow “K0” in a cutting mode asdescribed in greater detail below with reference to FIG. 12. Theembodiment of instrument 10 described herein includes a knife lockmechanism (see FIG. 13) to prevent the knife blade 54 a from advancingto the position depicted in FIG. 2B when the end effector 16 is in theopen configuration. Other embodiments are envisioned, however, whichpermit the knife blade 54 a to be advanced when the end effector 16 isin the open configuration.

Referring now to FIG. 2C, the end effector 16 is moved through a thirdmode of motion herein referred to as a “wrist roll.” The wrist roll maybe initiated by rotating the wrist roll knob 44 (FIG. 1) in eitherdirection. The end effector 16 is rotated about the end effector axisB-B through any wrist roll angle “δ” until an orientation of the endeffector 16 is achieved that is appropriate for contacting tissue. Oncepositioned and oriented, the end effector 16 may be moved through afourth mode of motion herein referred to as the “clamping mode.” Theclamping mode may be initiated to move the jaw members 30, 32 in thedirection of arrows “C0” to the closed configuration depicted in FIG. 2Dto capture tissue therebetween. In this closed configuration, anappropriate clamping force along with electrosurgical energy may bedelivered to the tissue to seal the tissue. Thereafter, the surgeon mayelect to sever the tissue captured between the jaws 30, 32 by advancingthe knife blade 54 a (FIG. 2B) through the tissue in a fifth mode ofmotion herein referred to as the “cutting mode.”

Referring now to FIG. 3, a coaxial drive assembly 100 is disposedgenerally within the handle 12. The coaxial drive assembly 100 receivesmechanical motion from the actuators (e.g., articulation trigger 40,shoulder roll knob 42, wrist roll knob 44, pivoting handle 46, lockinglever 52 and knife spool 54), and transmits a corresponding motionthrough the elongated shaft 18 to induce the various modes of motion inthe end effector 16 discussed above. The mechanical motion transmittedthrough the elongated shaft 18 is either longitudinal motion directed ina general direction parallel to the longitudinal axis A-A, or rotationalmotion about the longitudinal axis A-A. Accordingly, the drive assembly100 may be referred to as “coaxial.”

Referring now to FIG. 4, the coaxial drive assembly 100 is depicted in afirst “home” configuration corresponding to the “home” configuration ofthe elongated shaft 18 depicted in FIG. 1. The drive assembly 100includes two main subsystems 102 and 104. A first positioning subsystem102 drives the articulation and shoulder roll modes, and provides a lockto maintain the end effector 16 at particular angles “α” and “β.” Thesecond subsystem 104 drives the wrist roll, clamping and cutting modes.The two subsystems 102, 104 operate independently of one another in thatthe operation one subsystem, e.g. 102, does not transfer motion to theother subsystem, e.g. 104.

The first positioning subsystem 102 includes an articulation sphere 106coupled to tendons 110 by a pair of tendon pins 112. The articulationsphere 106 (depicted in greater detail in FIG. 14A) is generallyspherical in shape and includes a pair of coupling channels 114 (FIG.14A) therein for receiving the tendon pins 112. The tendon pins 112 arecaptured within the connection channels 114, and the tendons 110 aresecured to the tendon pins 112. Thus, the tendons 110 are coupled to thearticulation sphere 106. Tendon relief slots 116 (FIG. 14A) extendlongitudinally from the connection channels 114 and provide strainrelief and permit rotational movement of the articulation sphere 106without interfering with the tendons 110.

A pair of pivot axles 118 (FIG. 14A) extend laterally from thearticulation sphere 106 in a diametrically opposed fashion. The pivotaxles 118 define a pivot axis C-C (FIG. 14A) about which thearticulation sphere 106 may be induced to pivot. A drive slot 120 isdefined in the articulation sphere 106 laterally spaced from the pivotaxis C-C such that longitudinal motion imparted to the drive slots 120induces pivotal motion in the articulation sphere 106 about the pivotaxis C-C. A second drive slot 120′ is formed opposite drive slot 120.The second drive slot 120′ provides additional symmetry to thearticulation sphere 106 to ease manufacturing and assembly. However,second drive slot 120′ is inactive in the embodiment of drive assembly100 discussed herein with reference to FIG. 4, i.e., the second driveslot 120′ is not engaged to impart pivotal motion to the articulationsphere 106. A central opening 122 is formed longitudinally through thearticulation sphere 106. The central opening 122 permits passage ofvarious components through the articulation sphere 106 withoutinterference with the motion of the articulation sphere 106.

An articulation spool 124 (depicted in greater detail in FIG. 14B) isgenerally cylindrical in shape and radially surrounds the articulationsphere 106. A drive post 126 extends into an interior of thearticulation spool 124 such that the drive post 126 may engage the driveslot 120 of the articulation sphere 106. A spool feature 128 at theproximal end of the articulation spool 124 provides a double-flangeinterface for engaging the articulation trigger 40 (see FIG. 3).Clearance slots 130 (FIG. 14B) are formed in the walls of thearticulation spool 124 to provide clearance for the axles 118 of thearticulation sphere 106.

Referring now to FIG. 5, the coaxial drive assembly is moved to a secondconfiguration to initiate motion of the end effector 16 in thearticulation mode. The articulation spool 124 may be drivenlongitudinally to induce rotational movement in the articulation sphere106. For example, a surgeon may drive articulation trigger 40 distallyin the direction of arrow “A1” (FIG. 3), which in turn drives thearticulation spool 124 distally in the direction of arrows “A2.” Thedrive post 126 drives the drive slot 120 distally, and since the axles118 (FIG. 14A) of the articulation sphere 106 are longitudinallyrestrained (as discussed below), the articulation sphere 106 is inducedto rotate in the direction of arrow “A3” about the pivot axis C-C. Thisrotation induces differential longitudinal tension and motion in thetendons 110 as indicated by arrows “A4.” As discussed above withreference to FIG. 2A, differential longitudinal motion in the tendons110 imparts movement in the end effector 116 in a first direction in thearticulation mode. A surgeon may similarly induce articulation of theend effector 116 in an opposite direction by drawing the articulationtrigger 40 proximally.

To induce motion of the end effector 16 in the articulation mode, thedrive assembly 100 employs tension in the tendons 110 and a systemspring rate. The tendons 110 are preloaded with a tensile force tomanage the amount of slack or play in the articulation mode. In someinstances, an adjustment to the amount of tension in the tendons mayfacilitate use of the coaxial drive assembly 100. For instance, overtime, fatigue or creep tension losses may occur in the tendons 110. Thisloss in tension may be associated with a decline in responsiveness ofthe device 10, which may frustrate the intent of a surgeon. The abilityto increase the tension in the tendons 110 may improve the survivabilityof the drive assembly 100 and facilitate operation of the instrument 10.In other instances, the general tension in the tendons 110 may beincreased to prohibit any inadvertent movement of the end effector 16 inthe articulation mode. In this manner, an operator may lock the endeffector 16 at a particular angle “α” (FIG. 2A) with respect to thelongitudinal axis A-A.

Referring now to FIG. 6A, a tendon preload-and-locking mechanism 130 amay be incorporated into the device 10 at any convenient longitudinallocation, and may be employed to adjust the tension in a tendon 110. Themechanism 130 a includes first and second stationary tendon guides 132and 134, respectively. Each of the stationary tendon guides 132, 134 isgenerally ring shaped and centered about the longitudinal axis A-A. Thestationary tendon guides 132, 134 have a fixed longitudinal positionwith respect to the stationary handle 48 (FIG. 1), but in someembodiments may be free to rotate about the longitudinal axis A-A.Tendon 110 defines a tensile axis and is situated to extend through therings and to contact an inner surface of each of the guides 132, 134.The first fixed tendon guide 132 has a smaller inner diameter than thesecond fixed tendon guide 134, and thus the tendon 110 extends obliquelywith respect to the longitudinal axis A-A. The first fixed tendon guide132 restrains the tendon 110 at a first lateral distance from thelongitudinal axis A-A that is less than a second lateral distance fromthe longitudinal axis A-A at which the second fixed tendon guide 134restrains the tendon 110. A straight-line distance between the points ofcontact between the tendon 110 and the stationary guides 132, 134 isrepresented by dimension “L0.” Arranging the first tendon guide 132distally with respect to the second fixed tendon guide 134 may directthe tendon 110 toward the longitudinal axis A-A for passage through theelongated shaft 18.

Arranged longitudinally between the stationary tendon guides 132, 134 isa movable guide 136 a. Similar to the stationary tendon guides 132, 134,the movable guide 136 a is ring shaped and centered about thelongitudinal axis A-A. The movable guide 136 a has an intermediatediameter, i.e., greater than the first stationary tendon guide 132 andless than the second stationary tendon guide 134 to restrain the tendon110 at a third lateral distance from the longitudinal axis. The movableguide 136 a is movable in the direction of arrow “G0” along thelongitudinal axis A-A by an actuator (not shown), which is accessible toan operator at least during maintenance of the instrument 10. Themovable guide 136 a may be arranged such that an inner surface of themovable guide 136 contacts the tendon 110 as depicted in FIG. 6A, andexerts a force on the tendon 110 in the direction toward thelongitudinal axis A-A. The tendon 110, thus assumes an angularconfiguration defining angle “Ω” with an apex at the movable guide 136 aand forming straight-line segments between the movable guide 136 a andeach of the stationary guides 132, 134. These segments have lengthsrepresented by the dimensions “L1” and “L2.”

In this angular configuration, the total length (L1+L2) of the tendon110 between the stationary guides 132, 134 is greater than thestraight-line distance (L0) between the stationary guides 132, 134.Moving the movable guide 136 a longitudinally in the direction of arrow“G0” toward the second stationary guide 134 increases the angle “Ω” andthe total length (L1+L2) of the tendon 110 between the guides. Thisincrease in length is associated with an increase in tension in thetendon 110 due to structural elastic deformation, compensating springload, or elongation.

The longitudinal position of the movable guide 136 a may be fixed at alocation wherein an appropriate tension is maintained in the tendon 110to suit a particular purpose. For example, the movable guide 136 a maybe moved sufficiently close to the second stationary guide 134 that thefrictional force between the tendon 110 and the guides 132, 134, 136 ais sufficient to effectively lock the position of the tendon 110. Inthis way, the tendon preload-and-locking mechanism 130 a may be used toprevent inadvertent articulation of the end effector 16.

Referring now to FIG. 6B, an alternate embodiment of apreload-and-locking mechanism is depicted generally as 130 b. Themechanism 130 b includes tendon 110 situated through stationary guides132, 134 as described above with reference to FIG. 6A. A movable guide136 b includes an irregular inner profile defining a cam surface 138.The movable guide 136 b may be rotated about the axis A-A in thedirection of arrow “G1” to vary the distance from the axis A-A in whichthe tendon 110 contacts the cam surface 138. Thus, the path of tendon110 between the stationary guides 132, 134 is varied along with thecontact force encountered by the tendon 110 and the tension in tendon110.

FIG. 6C depicts another embodiment of a preload-and-locking mechanism130 c in which a movable tendon guide 136 c contacts tendon 110 in anopposite direction to bend the tendon 110 generally away from thelongitudinal axis A-A. A cam surface 140 is provided on an outer surfaceof the movable tendon guide 136 c to vary the distance from thelongitudinal axis A-A in which the tendon contacts the tendon guide 136c. Thus, the tension in tendon 110 may be adjusted by rotating themovable tendon guide 136 c about the longitudinal axis in the directionof arrow “G2.” Alternatively, the tension may be adjusted by movement ofthe moveable tendon guide 136 c in the longitudinal direction of arrow“G3” toward the first tendon 132 to increase the tension in the tendon.

Referring now to FIG. 7, the coaxial drive assembly 100 is moved to athird configuration inducing the end effector 16 to move in the shoulderroll mode. A surgeon may engage external bosses 142 on the shoulder rollknob 42 to rotate the shoulder roll knob 42 about the longitudinal axisA-A in the direction of arrows “S1.” The shoulder roll knob 42 isfixedly coupled to the outer tubular member 60 of the elongated shaft18, and thus the outer tubular member 60 rotates in the direction ofarrow “S2” along with the shoulder roll knob 42. A distal end of theouter tubular member 60 is fixedly coupled to a trailing segment 56 b(FIG. 2A) of the distal portion 22 of the elongated shaft 18. Thus, theentire distal portion 22 of the elongated shaft 18 rotates along withthe shoulder roll knob 42 to achieve the motion in the shoulder rollmode.

Rotation of the shoulder roll knob 42 induces a corresponding rotationin each element of the positioning subsystem 102 about the longitudinalaxis A-A. An interior surface 148 a (FIG. 14C) of the shoulder roll knob42 may be splined to include ridges (not shown) extending longitudinallytherein to correspond with longitudinal channels (not shown) on anexterior surface 148 b (FIG. 14B) of the articulation spool 124. Theridges and channels allow the articulation spool 124 to movelongitudinally within the interior of the shoulder roll knob 42 whileproviding a means for transmitting torque from the shoulder roll knob 42to the articulation spool 124. This type of arrangement is hereinafterdenoted a “splined slip joint.”

Many of the other components of the coaxial drive assembly 100 maydefine a splined slip joint with radially adjacent components such thatthe radially adjacent components rotate together while maintainingindependent longitudinal motion capabilities. For example, a splinedslip joint is also defined between the articulation spool 124 and alocking collar 154. Thus, the locking collar 154 rotates along with thearticulation spool 124 and the shoulder roll knob 42. The locking collar154 is fixedly coupled to a flange 154 a at a proximal end thereof. Theflange 154 a includes a series of radially oriented teeth and detentsthereon, which may be engaged by a flexible rib (not shown) projectingfrom the stationary handle 48. Since the splined slip joints permit theflange 154 a to rotate concurrently with the shoulder roll knob 42, theteeth on the surface of the flange 154 a may be employed to index theshoulder roll mode and to provide a variable resistance lock forshoulder roll rotation. This indexed rotation of the flange 154 aprovides tactile feedback to the surgeon while employing the shoulderroll mode, and stabilizes the shoulder roll mode once an appropriateshoulder roll angle “β” (FIG. 2B) has been established. The splined slipjoints also permit the locking collar 154 to move in a longitudinaldirection to provide an additional lock to the articulation and shoulderroll modes as described below with reference to FIGS. 3 and 8.

The splined slip joints defined in the positioning subsystem 102 permitthe entire positioning subsystem 102 to rotate concurrently to ensurethat the tendons 110 do not become entangled in the shoulder roll mode.The articulation mode is thus independent of the shoulder roll mode inthat the articulation mode may be initiated irrespective of therotational position (e.g. the angle “β,” FIG. 2B), of the end effector.Likewise, the shoulder roll mode may be initiated irrespective of thearticulation angle (e.g. the angle “α,” FIG. 2A).

The interior surface 148 a (FIG. 14C) of the shoulder roll knob 42includes clearance channels 150 therein. The clearance channels 150 arediametrically opposed to receive the axles 118 (FIG. 14A) of thearticulation sphere 106. The axles 118 are longitudinally restrained inthe clearance channels 150. The shoulder roll knob 42 also includes atapered interior surface 152 a extending between the interior surface148 and a ring surface 152 b. The tapered surface 152 a may function asa conical volume feeder cone to guide the tendons 110 from thearticulation sphere 106 to the ring surface 152 b. The ring surface 152b guides the tendons 110 through the elongated shaft 18, and may serveas the first stationary tendon guide 132 as described above withreference to FIGS. 6A through 6C.

Referring now to FIGS. 3 and 8, the coaxial drive assembly 100 may bemoved to a fourth configuration to prohibit motion of the end effector16 in the articulation and shoulder roll modes simultaneously. Whensatisfactory articulation and shoulder roll positions have beenachieved, a surgeon may manipulate locking lever 52 as depicted in FIG.3 to induce appropriate movement of the locking collar 154 as depictedin FIG. 8. The locking lever 52 (FIG. 3) is supported to rotate aboutthe longitudinal axis A-A in the direction of arrows “F1” and includes acam surface on a proximal end thereof. The cam surface on the lockinglever 52 engages a corresponding surface on a locking slider 156. Thelocking slider 156 is restrained from rotating by a splined slip jointwith the handle portion 12 or a similar feature, and thus, rotation ofthe locking lever 52 in the direction of arrow “F1” induces longitudinalmotion in the locking slider 156 in the direction of arrow “F2.” Thelocking slider 156 engages the flange 154 a that is coupled to lockingcollar 154 such that the longitudinal motion in the locking slider 156is transmitted to the locking collar 154 as depicted in FIG. 8. Theengagement of the locking slider 156 with the flange 154 a permits theindexed rotational motion of the flange 154 a in the shoulder roll modeas described above with reference to FIG. 7 while transmitting thelongitudinal motion in the locking slider 156 to the locking collar 154.

As depicted in FIG. 8, the locking collar 154 is induced to move in thedirection of arrow “F0” in response to the longitudinal motion of thelocking slider 156. The locking collar 154 is moved proximally in thedirection of arrow “F0” until an interior concave surface 156 (FIG. 14D)of the locking collar 154 contacts the articulation sphere 106. Thearticulation sphere 106 encounters a frictional resistance to motionsince the tendons 110 exhibit a fixed length, and thus do not permit thearticulation sphere 106 to move proximally. The frictional resistance tomotion prohibits the articulation sphere 106 from pivoting about thepivot axis C-C (FIG. 14A) and thus prohibits motion of the end effector16 in the articulation mode.

The frictional resistance generated between the locking collar 154 andthe articulation sphere 106 also supplements the resistance to rotationprovided by the indexing feature on the flange 154 a as discussed abovewith reference to FIG. 7. The frictional resistance between thearticulation sphere 106 and the locking collar 154 discourages rotationof the locking collar 154 about the longitudinal axis A-A. As discussedabove, the locking collar 154 may include longitudinal ridges andchannels on an outer surface thereof to define a splined slip joint withcorresponding ridges and channels on an interior of the articulationspool 124. The locking collar 154 includes longitudinal slots 160 (FIG.14D) therein to permit passage of the axles 118 of the articulationsphere 106 and the drive post 126 of the articulation spool 124. Thefrictional resistance to rotation in the locking collar 154 may thus betransmitted to the articulation spool 124, and further to the shoulderroll knob 42 through the splined slip joint defined between articulationspool 124 and the shoulder roll knob 42. Thus, the locking collar 154provides a more positive stop to the shoulder roll mode than theindexing feature on the flange 154 a alone.

Referring now to FIG. 9, the coaxial drive assembly 100 is moved to afifth configuration to induce the end effector 16 to move in the wristroll mode. The wrist roll mode is driven by subsystem 104, whichoperates independently of the positioning subsystem 102. Thus, the wristroll mode, and the other modes of motion driven by the subsystem 104,may be initiated irrespective of the configuration of the positioningsubsystem 102. To initiate the wrist roll mode, a surgeon may engageexternal bosses 162 on the wrist roll knob 44 to rotate the wrist rollknob 44 about the longitudinal axis A-A in the direction of arrows “W1.”The wrist roll knob 44 is coupled to a jaw spool 164 through a splinedslip joint such that the jaw spool 164 rotates in the direction of arrow“W2” along with the wrist roll knob 44. The jaw spool 164 is fixedlycoupled to an intermediate tubular member 166 of the elongated shaft 18,and thus the intermediate tubular member 166 rotates in the direction ofarrow “W3” along with the wrist roll knob 44. The intermediate tubularmember 166 extends distally through the positioning subsystem 102 andthrough the outer tubular member 60. A distal end of the intermediatetubular member 166 is coupled to a torsion cable 166 a (FIG. 10A), whichtransmits torque from the intermediate tubular member 166 to a rolljoint 168 a (FIG. 10A). The roll joint 168 supports the end effector 16,and thus the torque transmitted to the roll joint 168 a may induce theend effector 16 to rotate in the wrist roll mode. The torsion cable 166a is flexible, and extends through the articulating distal portion 22 ofthe elongated shaft 18 such that torque may be transmitted through thedistal portion 22 regardless of the articulation angle “α” achieved.

Referring now to FIG. 10A, the torsion cable 166 a extends to a rolljoint 168 a. The roll joint 168 a includes a first tubular structure 170and a second tubular structure 172. The first tubular structure 170extends distally from the elongated shaft 18 where a shoulder 170 a isprovided to rigidly couple the first tubular structure 170 to leadingsegment 56 a. The second tubular structure 172 is rigidly coupled to anend effector housing 16 a (see also FIG. 2C) that supports the endeffector 16. The first and second tubular structures 170, 172 arecoupled to one another by a bearing set 174, which permits the secondtubular structure 172 to rotate relative to the first tubular structure170 about end effector axis B-B. The bearing set 174 may be provided asa duplex pair, e.g. a pre-manufactured pair of bearings with a preciselycontrolled distance between races to provide a particular pre-load tothe bearings, and may be fixedly coupled to the first and second tubularstructures 170, 172 by welding or a similar process. The torsion cable166 a is coupled to the second tubular structure 172 to transmit torquethereto. When the intermediate tubular member 166 (FIG. 9) is induced torotate in the direction of arrow “W3” (FIG. 9) by the rotation of thewrist roll knob 44, the torsion cable 166 a induces the second tubularstructure 172 to rotate in the direction of arrows “W4.” Since thesecond tubular structure 172 is rigidly coupled to the end effectorhousing 16 a, the end effector 16 may be moved through the wrist rollmode in the direction of arrows “W0” (FIG. 2C) about the end effectoraxis B-B.

The first tubular structure 170 includes a cable wrap volume 176 thereinto provide sufficient space for electrosurgical conductor 178 to becoiled about the end effector axis B-B. The cable wrap volume 176extends between a bulkhead 176 a and the bearing set 174. Theelectrosurgical conductor 178 is configured to conduct electrosurgicalenergy to the end effector 16 in response to an appropriate actuation offinger trigger 50 and/or push button 50 a (FIG. 1). Conductor 178 mayexhibit a round, flat or other geometry to facilitate winding orunwinding of the conductor 178 within the cable wrap volume 176. Windingthe conductor 178 a permits the end effector 16 to rotate in the wristroll mode without unduly straining or tangling the conductor 178 a.Sufficient slack is provided in the conductor 178 a to permit rotationof the end effector 16 in either direction. The number of wrist rollrotations permitted may be limited by the geometric construction andwinding configuration of the conductor 178 a. To relieve any unduestrain on the conductor 178 that may occur as a result of reaching thelimit of wrist-rolls, a structural stop 180 may be provided. Thestructural stop 180 is positioned such that the second tubular structure172 engages the stop 180 to prohibit further rotational motion beforethe slack in the conductor 178 a is taken up. First and second tubularstructures 170, 172 are include a longitudinal bore extendingtherethrough to permit passage of various implements to effect motion inthe end effector 16. For example, a reciprocating member 188 islongitudinally movable in the clamping mode to open and close the jaws,and compression member 194 is longitudinally movable in the cutting modeto advance the knife blade.

Referring now to FIG. 10B, an alternate embodiment of a roll joint isdepicted generally as 168 b. The roll joint 168 b includes a bearing set174 coupled between first and second tubular structures 170, 172 asdescribed above with reference to FIG. 10A. An electrosurgical conductor178 b extends to an electrically conductive slip ring 182 defined on theinterior of first tubular member 170. An electrically conductivereceptor 184 is coupled to the second tubular structure 172 such thatthe receptor 184 maintains electrical contact with the slip ring 182regardless of the wrist roll angle “γ” (FIG. 2C) achieved. The receptor184 is in electrical communication with the end effector 16 throughelectrosurgical conductor 178 c, and thus the end effector 16 may beprovided with an electrosurgical current. The slip ring arrangement ofroll joint 168 b permits an unlimited number of wrist roll rotations ofthe end effector 16.

Referring now to FIG. 11, the coaxial drive assembly 100 is moved to asixth configuration for moving the end effector 16 in the clamping mode.As discussed above with reference to FIG. 1, the clamping mode may beinitiated to open and close the jaw members 30, 32. To close the jaws30, 32, (see FIG. 2D) the jaw spool 164 is moved longitudinally in theproximal direction of arrow “C2” by the approximation of the pivotinghandle 46 with the stationary handle 48 in the direction of arrow “C1.”The pivoting handle 46 engages the jaw spool 164 between drive flanges186 such that jaw spool 164 may be moved longitudinally in eitherdirection by the approximation and separation of the pivoting handle 46with respect to the stationary handle 48. Since the jaw spool 164 isfixedly coupled to the intermediate tube member 166 as described abovewith reference to FIG. 9, the proximal longitudinal motion in the jawspool 164 is transmitted to the intermediate tube member 166. Thus, theintermediate tube member 166 moves in the proximal direction asindicated by arrow “C3.”

A distal end of the intermediate tubular member 166 is coupled to anarrow reciprocating member 188 (FIG. 10A). The reciprocating member 188transmits the proximal motion of the intermediate tube member 166through the articulating distal portion 22 of the elongated shaft 18.The reciprocating member 188 may be a relatively thin wire or baroriented such that the reciprocating member 188 is sufficiently flexibleto bend in a single plane to accommodate any articulation angle “α”while remaining sufficiently rigid to transmit sufficient tensile andcompressive forces to open and close jaw members 30, 32. The jaw members30, 32 may include any appropriate feature such that the jaw members 30,32 are induced to close by the proximal longitudinal motion in thereciprocating member 188. For example, the jaw members 30, 32 mayexhibit cam features (not shown) thereon to transform the longitudinalmotion of the reciprocating member 188 into pivotal motion of the jawmembers 30, 32 as in the instrument described in U.S. Pat. No. 7,083,618to Couture et al., entitled “VESSEL SEALER AND DIVIDER.”

When the jaw members 30, 32 are moved to the closed configuration toclamp tissue therebetween, an electrosurgical tissue seal may becreated. To form an effective tissue seal, in one embodiment, arelatively high clamping force is typically generated to impart aclosure pressure on the tissue in the range of from about 3 kg/cm² toabout 16 kg/cm². An appropriate gap distance of about 0.001 inches toabout 0.006 inches may be maintained between the opposing jaw members30, 32, although other gap distances are contemplated. Since at leastone of the jaw members 30, 32 is connected to a source of electricalenergy 50 b (see FIG. 1), a surgeon may manipulate finger trigger 50and/or push button 50 a to initiate transmission of electrosurgicalenergy through tissue to effectuate a seal.

Referring now to FIG. 12, the coaxial drive assembly 100 is moved to aseventh configuration for advancing a knife blade 54 a (see FIG. 2B) toinduce end effector motion in the cutting mode. The knife blade may beadvanced through the jaw members 30, 32 to sever or transect tissue oncea tissue seal has been formed. The knife spool 56 forms a splined slipjoint with the jaw spool 164 such that a surgeon may move the knifespool 56 longitudinally in the distal direction of arrow “K1” againstthe bias of a spring 190 (FIG. 13). The knife spool 56 is fixedlycoupled to an inner tubular member 192 such that the distal longitudinalmotion imparted to the knife spool 56 is transmitted to the innertubular member 192. Thus, the inner tubular member 192 moves distally asindicated by arrow “K2.” A distal end of the inner tubular member 192 isfixedly coupled to the bendable compression member 194 (FIG. 10A), whichis configured similar to the reciprocating member 188 described abovewith reference to FIGS. 11 and 10A. Thus, the compression member 194 maytransmit longitudinal motion through the articulating distal end 22 ofthe elongated shaft 18 regardless of the articulation angle “α”achieved. A distal end of the compression member 194 is, in turn,fixedly coupled to the knife blade 54 a. Thus, the longitudinal motionimparted to the knife spool 56 may be transmitted ultimately to theknife blade 54 a to drive the knife blade 54 a through tissue. When thesurgeon releases the knife spool 56, the bias of spring 190 tends toretract the knife blade 54 a.

Referring now to FIG. 13, a knife lock mechanism is depicted generallyas 200. The knife lock mechanism 200 is configured to permit advancementof the knife blade 54 a (FIG. 2B) in the cutting mode only when the jawmembers 30, 32 have been moved to the closed configuration depicted inFIG. 2D. The mechanism 200 includes a latch piston 202 mounted withinthe stationary handle 48. The latch piston 202 is normally biased bycompression spring 204 to a position in which the latch piston 202prohibits distal translation of the knife spool 56. A latch releasepiston 206 is biased by compression spring 208 in a distal directionsuch that a distal end of the latch release piston 206 abuts one of theflanges 186 of the jaw spool 164. A proximal end of the latch releasepiston 206 includes a ramped cam surface 210 in engagement with thelatch piston 202.

A surgeon may approximate the pivoting handle 46 with the stationaryhandle 48 to induce longitudinal motion in the jaw spool 164 in thedirection of arrow “C2” and thereby move the jaw members 30, 32 to theclosed configuration as described above with reference to FIG. 11. Thejaw spool 164 bears on the release piston 206 such that the releasepiston 206 moves in the proximal direction indicated by arrow “C4”against the bias of spring 208. As the release piston 206 movesproximally, the ramped cam surface 210 engages the latch piston 202 suchthat the latch piston 202 is induced to move in the direction of arrow“C5” against the bias of spring 204. The latch piston 202 is therebymoved to a position that does not interfere with longitudinal motion ofthe knife spool 56 in the direction of arrow “K1”. Thus, motion in thecutting mode may be initiated. When the surgeon separates the pivotinghandle 46 from the stationary handle 48, the bias of the springs 204 and208 return the latch piston 202 to its normally biased position. In thenormally biased position, the latch piston 202 extends into the path ofthe knife spool 56 prohibiting motion of the knife spool 56.

Although the foregoing disclosure has been described in some detail byway of illustration and example, for purposes of clarity orunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the appended claims.

What is claimed is:
 1. A surgical instrument, comprising: an elongatedshaft having a proximal portion and a distal portion that arearticulable relative to one another, the proximal portion defining afirst axis and the distal portion defining a second axis; and a rolljoint disposed at a distal end of the elongated shaft, the roll jointincluding: a first tubular structure extending distally from theelongated shaft and having an inner surface defining a cable wrapvolume; a second tubular structure coupled to the first tubularstructure, the second tubular structure rotatable about the second axisrelative to the first tubular structure; and a conductor coiled againstthe inner surface about the second axis within the cable wrap volumesuch that rotation of the second tubular structure about the second axisin a first direction unwinds the conductor, the conductor extending fromthe proximal portion of the elongated shaft through the second tubularstructure.
 2. The instrument according to claim 1, further comprising anend effector disposed at a distal end of the second tubular structure,the conductor configured to connect the end effector to a source ofelectrosurgical energy through the proximal portion of the elongatedshaft.
 3. The instrument according to claim 2, wherein the proximalportion of the elongated shaft is rotatable about the first axis.
 4. Theinstrument according to claim 3, further comprising a handle coupled tothe proximal portion of the elongated shaft, proximal portion rotatablerelative to the handle.
 5. The instrument according to claim 4, whereinthe handle includes the source of electrosurgical energy.
 6. Theinstrument according to claim 2, wherein the end effector includes apair of opposable jaw members movable between an open configuration forreceiving tissue and a closed configuration for maintaining a closurepressure on the tissue.
 7. The instrument according to claim 6, whereinthe end effector is coupled to a reciprocating member longitudinallymovable to induce movement of the jaw members between the open andclosed configurations, the reciprocating member extending through alongitudinal bore defined through the roll joint.
 8. The instrumentaccording to claim 1, wherein the roll joint further comprises astructural stop protruding from at least one of the first and secondtubular structures and engaging the other of the first and secondtubular structures to limit rotation of the second tubular structure. 9.The instrument according to claim 1, wherein the first and secondtubular structures are coupled to one another by a bearing set.
 10. Theinstrument according to claim 1, wherein the second tubular structure iscoupled to a drive member, the drive member extending through the rolljoint and configured to transmit torque to the second tubular structure.11. The instrument according to claim 10, wherein the elongated shaftincludes an articulating portion between the proximal and distalportions, the drive member extending through the articulating portion.12. The instrument according to claim 1, wherein a portion of the secondtubular structure is disposed within the first tubular structure. 13.The instrument according to claim 1, wherein an outer surface of thefirst tubular structure forms a contiguous surface with an outer surfaceof the second tubular structure.
 14. A surgical instrument, comprising:an elongated shaft having a proximal portion and a distal portion, theproximal portion defining a first axis and the distal portion defining asecond axis, the proximal portion rotatable about the first axis; and aroll joint disposed at a distal end of the elongated shaft, the rolljoint including: a first tubular structure extending distally from theelongated shaft and having an inner surface defining a cable wrapvolume; a second tubular structure coupled to the first tubularstructure, the second tubular structure rotatable about the second axisrelative to the first tubular structure; and a conductor coiled againstthe inner surface about the second axis within the cable wrap volumesuch that rotation of the second tubular structure about the second axisin a first direction unwinds the conductor, the conductor extending fromthe proximal portion of the elongated shaft through the second tubularstructure.
 15. The instrument according to claim 14, wherein theelongated shaft includes an articulating portion between the proximaland distal portions configured to pivot the distal portion relative tothe proximal portion.
 16. The instrument according to claim 14, furthercomprising a handle coupled to the proximal portion of the elongatedshaft, proximal portion rotatable relative to the handle.